I'm not sure if I understand what you want to achieve. Please note that swimlanes contain other graph elements and not textual data like Excel tables.
Unfortunately, it is not possible to create swimlanes (or tables or groups) with the Excel import feature. This can create only regular nodes and edges. There is already a related feature request which you might vote up: http://yed.yworks.com/support/qa/497/
After importing Excel data into regular nodes, it's of course possible to edit the graph in any way, that is, you can manually add swimlanes and manually place the (imported) nodes into their respective swimlanes, see the related yEd manual page.